Liquid conductor heater



Oct. 11, 1932. HANKS 1,881,531

LIQUID CONDUCTOR HEATER Filed Feb. 27, 1930 Patented Oct. 11, 1932UNITED STATES PATENT OFFICE mAnsHALL w. HANKS, or MADISON, wIsooNsINLIQUID CONDUCTOR HEATER Application filed February 27, 1930. Serial No.431,712.

This invention relates to improvements in which one embodiment isillustrated. In the liquid conductor heatersand its purpose is drawing,to provide improved means for reducing the Figure 1 shows a centralvertical section electric shock hazard incident to the operathrough oneform of liquid conductor heattion of such devices. Liquid conductorheater with the circuit connections illustrated ers of the type referredto commonly comdiagrammatically; prise a vessel containing a pair ofspaced Fig. 2 shows a horizontal section taken on electrodes which areadapted to be connectthe line 22 of Fig. 1; and ed by a liquidconductor, such as water, F 1g. 3 shows a horizontal section taken onwhich is heated by the passage of current e llne 33 of Fig. 1.therethrough, with resulting vaporization, As Ill strated in thedrawing, the invenuntil finally the entire quantity of liquid is l Illsernbodied in a liquid conductor heater vaporized with the result thatthe flow of Compris ng a vessel 10 formed of porcelain or urr nt i t tilly h t fl, althou h other su table insulating material which has theelectrodes remain electrically alive, asformed lntegrally therewith adownwardly suming that the elctrical conductors leading eXtendmg annularflange 11 adapted to rest to the device remain connected to the source pn a table o her support 12. On the of supply, which is the usualcondition when pper Surface of the bottom wall 18 of the the liquidconductor is completely vaporized. CaS ng there is mounted a plateelectrode 14 O id f th l t i p ly circuit i in the form of an annularring which extends commonly grounded and if the operator haparound thecentral projection 15 formed on pens to stand upon a damp surface andthe bottom wall. A pair of terminal posts touches the wet surface of thevessel during 16 are secured to the underside of the elecits operationor after the current has ceased trode 14 and extend downwardly throughto flow due to the evaporation of the liquid, apertures in the bottomwall 13, with which there is likelihood of shock which, while notapertures they have a fluid tight connection ordinarily dangerous, tendsto retard the deso that the liquid conductor contained within velopmentof the practical use of liquid conthe vessel will not escape; Extendingupd t h t wardly through the projection is an ex- The principal objectof the present inventernally threaded terminal post 17 which is 30 tionis to provide a liquid conductor heater threadedly engaged at its upperend by the in which there is greater safety from elec- Central hubportion 18 of another plate electric shocks than has been possible inthe types trode 19, which is in the form of a circular of liquidconductor heaters heretofore on the fiat plate having formed therein aplurality market. A further object is to provide a of apertures 19 andwhich rests at its outer 85 ,-liquid conductor heater adapted for use inedge on an annular shoulder 20 which is an electric circuit having oneside grounded formed on the inner surface of the wall of the and withwhich, when the electrodes are Vessel. The electrode 19 is thus spacedfrom properly connected to the circuit, the danger the lower electrode14 and is adapted to en- 40 of shock is entirely eliminated, while thegage the shoulder 20 when in its normal posi 9 danger of shock, if theelectrodes are imtion. properly connected in the circuit, is no great-An electric conductor 21 leading from the or than it was in the types ofliquid consource of supply is passed through an aperductor heatersheretofore known. Other ture 22 in the side of the flange l1 and isconobjects of the invention relate to various feanected to one of theterminal posts 16 by 96 tures of construction and arrangement whichmeans of a clamping nut 23. Another elecwill appear more fullyhereinafter. tric conductor 24, forming the opposite side The nature ofthe invention will be unof the electric circuit, and having a ground(lerstood from the following specification connection as showndiagrammatically at 25, so taken with the accompanying drawing in isconnected to the other electrode through a downward extension 17 of theterminal posts which is engaged b a clamping nut 26. The extension 17 oft e central post 17 is engaged at its lower end by a nut 27 of sulatingmaterial having a reduced portion 27 which rotatably engages an apertureformed in the central part of a plate 28. This plate seats against anannular shoulder 29 formed on the underside of the vessel 10 and thusforms an enclosed chamber 30 within which the exposed metal contacts andparts of the conductors 21 and 24 are mounted, it being understood thatthe parts of the conductors 21 and 24 which extend outwardly from thevessel to the aperture 22 are suitably insulated from each other andfrom surrounding objects.

The space 31, above the upper electrode 19, forms the heating chamber inwhich a vessel containing material to be cooked, for example, is adaptedto be mounted and this container for the material to be cooked isadapted to be heated by the steam rising upwardly from the space betweenthe electrodes 14 and 19, due to the vaporization of the liquidconductor which establishes the electric circuit between theseelectrodes. A measured quantity of the liquid conductor is ordinarilyplaced in the vessel 10 to establish the electric circuit between theelectrodes 14 and 19 and as this liquid conductor is vaporized, the

. steam rises upwardly through the apertures 19 and a portion thereofcondenses on'the walls of the chamber 31 so that the surface of thevessel adjacent the upper part of the heating chamber is more or lessdamp, both during the operation of the device and after the flow ofcurrent has been cut off by the practically complete vaporization of themeasured quantity of liquid.

After the liquid has been evaporated to substantial dryness, even thoughthere is still some moisture on the interior surface of the vessel, thedanger of shocks with the connections shown, is eliminated due to thefact that the upper electrode 19 is in direct contact with the dampsurface of the vessel through the annular shoulder 20 and, since theelectrode 19 is connected to the grounded side of the line, there can beno shocks, even though the operator be standing'upon a damp surface.Should the device he incorrectly connected, that is, if the connectionsto the electrodes be reversed so that the lower electrode 14 isconnected to the grounded side of the line, the danger of shock is nogreater than it is in the types of devices heretofore known in which nomeans have been furnished for establishing a communication with the dampsurface of the vessel to prevent a flow of current from the ungroundedelectrodes. In the present invention, the flow of current from the lowerungrounded electrode is intercepted by the engagement with the annularshoulder 20 of the upper grounded electrode and thus this flow ofcurrent cannot continue upwardly over the interior wet surface of thevessel surrounding the heating chamber 31.

Although one form of the invention has been shown and described by wayof illustration, it will be understood that it may be constructed invarious other embodiments within the scope of the appended claims.

I claim:

1. A liquid conductor heater comprising a vessel adapted to contain aliquid conductor, a pair of spaced electrodes mounted in said vessel tobe connected by said liquid conductor, an electric circuit having oneside thereof grounded and having its terminals connected to said spacedelectrodes, and means for causing the current passing over the dampsurface of said vessel from one electrode to be intercepted by the otherelectrode connected to the grounded side of the line.

2. A liquid conductor heater comprising a. vessel adapted to contain aliquid conductor, a pair of spaced electrodes mounted in said vessel andadapted to be electrically connected by-said conductor, and an electriccircuit having one side of the line grounded and having its terminalsconnected to said electrodes, the electrode connected to the groundedside of the circuit being arranged above the other electrode and beingindirect contact with the interior surface of said vessel.

3. A liquid conductor heater comprising a.

vessel adapted to contain a liquid conductor,

a pair of spaced plate electrodes arranged in superimposed relation inthe bottom of said vessel, the uppermost electrode being perforated, anelectric circuit having one side of the line grounded and having itsgrounded terminal connected by a direct metallic connection to the saiduppermost electrode and the other terminal connected to said otherelectrode, and an annular shoulder formed on the interior surface ofsaid vessel and normally contacting directly with said uppermostelectrode.

4. A liquid conductor heater comprising a vessel adapted tocontain aliquid conductor, an electrode mounted in the bottom of said vessel,another perforated electrode mounted above and spaced from saidfirst-named electrode, an electric supply circuit having one sidethereof grounded, said circuit having its grounded terminal connected bya direct metallic connection to said upper electrode and its otherterminal connected to said lower electrode, and an annular shoulderformed on the inner wall of said vessel and engaging said upperelectrode.

5. A liquid conductor heater comprising a vessel adapted to contain aliquid conductor, an electrode mounted in the bottom of said vessel, aperforated electrode mounted above and spaced from said first-namedelectrode, an electric supply circuit having one side thereof grounded,a terminal post connected to the grounded side of said circuit andextending upwardly through said Vessel with its upper end directlyconnected to said per- 8 forated electrode, said circuit having theother side thereof connected to said lower electrode, and an annularshoulder formed on the inner wall of said vessel and contacting with theouter edge of said upper elec- 10 trode.

In testimony whereof, I have subscribed my name.

MARSHALL W. HANKS.

